(This article is an original article from Bisheng. It is forbidden to reprint, and reprinting must be corrected)In the modern binding process, different types of glue are often used for different requirements, so what kind of glue is used under what circumstances? This is a question that puzzles many people. In this article, we will discuss the use of different types of glue. I hope that through the introduction of this article, it will be of some help to everyone in future work.
At present, the more common adhesives mainly include animal-based adhesive materials, starch-based adhesive materials, casein-based adhesive materials, natural resin-based adhesive materials, cellulose-based adhesive materials, and synthetic resin-based adhesive materials. Below we introduce separately.
1. Animal adhesive materials:
(1) Bone glue
The main component of bone glue is water-insoluble protein. Another form of protein after heating and other treatments is called gelatin, which is soluble in hot water and has adhesive properties.
The glue film of bone glue is very strong and elastic after formation, which is determined by the long molecular chain of bone glue. This long molecular chain can change its arrangement without breaking, so it has a very good elasticity. If appropriate plasticizers are added during use, the elasticity of the film can be increased.
However, bone glue is not resistant to water. The water will cause the glue layer to swell and lose its bonding strength; its corrosion resistance is also not good. When the water content in the glue reaches more than 20%, it is easy to deteriorate. High temperature and high humidity will also cause changes.
Good bonding performance, high bonding strength, less moisture, quick drying, low price, and easy to use, especially for bonding and dextrin book covers, good results can be obtained.
Bone glue is best used for pasting book covers, which can avoid or reduce the unevenness of the book cover.
The raw materials for making gelatin are high-quality fresh animal skins, scraps and bones.
The composition of gelatin is similar to bone glue, but the purity is relatively high and the colloid is transparent. The melting temperature and coagulation temperature of gelatin are slightly different from bone glue.
The use method of gelatin is basically the same as bone glue, but because of its relatively high price, it is generally only used on some high-end books and periodicals and special processed products.
The characteristics of animal glue:
On the whole, animal glue has good adhesive properties, is easy to dry, and the price is relatively cheap, which is very popular with users. However, when using this kind of glue, the glue solution is only added after heating and melting with water, and has the disadvantages of brittleness after drying. Therefore, some auxiliary agents should be added during use to change some properties of the glue solution in order to obtain a better use effect. .
Glycerin can effectively prevent the adhesive layer from becoming brittle after drying.
Preservatives such as carbolic acid can prevent the glue from moldy deterioration.
Brighteners such as titanium dioxide can improve the color of glue.
Urea can increase the drying speed of the film at room temperature.
A small amount of terpineol (or silicone liquid, tributyl phosphate, etc.) can eliminate bubbles in the glue.
Second, starch-based adhesive materials
Starch-based adhesive material refers to an adhesive made of starch extracted from plant seeds, stems, tubers, etc.
(1) Gluten flour slurry
The gluten flour slurry is the gluten slurry obtained by washing the rice flour and the wheat flour (flour) with water or the gluten slurry obtained by fermenting the flour paste.
The gluten powder slurry binder has the advantages of fine texture and purity.
It is commonly used to bond the yam and paper mounted on the pasting reel, and the wrap angle of the book cover, letter, and book block of the thread.
(2) Flour paste
The main ingredient of flour paste is starch. The binding paste mainly includes wheat flour paste and Jiangmi flour paste.
It has a certain bonding strength, enough to bond paper, cardboard, cardboard, woven fabric, etc., and can be adjusted to different viscosities according to the requirements of the adhered object. However, other sticky materials sticking to the flour paste are easy to fall off when wet. When the temperature is high and the humidity is high, the flour paste is easy to ferment, produce enzymes, and spoil. The paste after fermentation has a sour odor, foaming on the surface, long green hair, and a greatly reduced viscosity, which affects the normal bonding process.
The bonding strength of flour paste is not high. It is suitable for the mounting of paper, cardboard and fabric and paper. It can also be used for the processing of general covers, ring backings, pulp backs, etc. It is not suitable for the work with high bonding strength.
Single and double pages, backing paper, paperback pulp back and paperback cover, sticky book back paper, etc.
Dextrin is a binder made of starch by acid or heat treatment or by the action of starch mold.
Compared with starch, it has high viscosity, fast drying, good transparency, and is not easy to spoil when left for a long time. Dextrin is easily soluble in hot water, slightly soluble in cold water, and has good adhesion properties.
Dextrin and paste have the same fluidity and penetration ability. They can penetrate, diffuse, and dry when wetted, and have a good bonding effect. Dextrin has many advantages, and there are many packaging forms from small to large, easy to use very popular.
It is suitable for bonding paper, fabric and other objects with certain absorption. It is worth mentioning that the use of dextrin in the mounting of cardboard is quite extensive.
Starch-based adhesive materials can also be mixed with other synthetic resin-based adhesives to change their properties and achieve better adhesion.
3. Natural resin bonding materials
Natural resin-based bonding materials are mainly derived from certain specific tree species, and are made of resin materials that flow out after cutting the bark.
This material is mainly used as an adhesion promoter during hot stamping.
Commonly used adhesion promoters include rosin powder and shellac.
4. Cellulose adhesive materials
The cellulose-based binding material is basically composed of a fiber-modified solution. It can bond paper, cardboard, cover, etc., and has good bonding performance.
(1) Carboxymethyl cellulose binder.
Carboxymethyl cellulose is an ether of cellulose and glycolic acid, also known as paper wool paste. This adhesive material is made by crushing paper wool and chemically processing it.
The drying strength of the carboxymethyl cellulose binder is stronger than the flour paste, the elasticity of the film is good, colorless and transparent, not afraid of bites by moths, no deterioration and spoilage, no precipitation, and long storage time. The viscosity can be adjusted arbitrarily, and can be mixed with paste or polyvinyl alcohol, etc., and can obtain a good bonding effect.
The drying speed of the carboxymethyl cellulose binder is slower than that of the starch-based binder. At the beginning of the bonding, the adhesive strength is insufficient. As the moisture evaporates and dries, the adhesive strength gradually becomes stronger. Good strength. Therefore, the pages or covers that are stuck during processing cannot be moved to avoid uneven or weak adhesion.
It can replace the use of starch-based adhesive materials, such as adhesive cover, paper, liner and so on.
(2) Methyl cellulose binder.
Methylcellulose is an ether of cellulose and methanol. The colloid is white or beige flakes. It can be dissolved in cold water. The surface tension decreases when dissolved. The glue will coagulate at 50 â„ƒ, but it will return to its original state after cooling Of solubility. Non-toxic, has good resistance to bacteria, and is also very stable to ultraviolet rays.
In the post-printing process, methyl cellulose is often used to bond the cover, etc., the glue is easy to apply, but sometimes blisters.
During the preparation, some tributyl phosphate can be added appropriately to prevent foaming.
5. Synthetic resin bonding materials
Synthetic resin, also known as artificial resin, is a resin formed by polymerization or polycondensation of monomers. Commonly used synthetic resin adhesive materials in the post-press process include: polyvinyl acetate, polyvinyl alcohol, 107 glue, EVA hot sol, etc.
(1) Polyvinyl acetate (PVAC).
Polyvinyl acetate is a polymer made by polymerizing vinyl acetate monomer. There are solution type and emulsion type according to different polymerization methods. The emulsion type is used in binding. Because of its milky color, it is also called white glue or latex.
PVAC is a milky white viscous liquid, slightly acidic, soluble in a variety of organic solvents, and resistant to dilute acids and alkalis. It is not afraid of bites by worms and moths, and it is not harmful to humans. The adhesive layer after PVAC curing is colorless and transparent, will not bring pollution to the paper, and it is a water-soluble emulsion that is easy to wash, can be thinned at will, and is easy to use; after drying, the PVAC adhesive layer has good toughness and does not damage the blade, which is suitable for binding .
The disadvantage is that this binder has poor water resistance and heat resistance.
PVAC adhesives are widely used, especially for the bonding of porous materials, such as paper, fabric, leather, wood.
PVAC adhesive can be used for single-page, double-page, pulp back, book backing paper, book backing cloth, bag cover, sweeping liner, etc., and can have very good results.
The PVAC binder can be mixed with flour paste, carboxymethyl cellulose, etc. to increase the viscosity of the fluid and at the same time reduce the cost.
PVAC is a water-soluble glue. The drying speed is similar to paste, it is very slow, and it is not easy to shape. If it is used to paste hardcover bookcases, the bookcases will be warped due to the penetration of moisture and short drying time.
PVAC adhesive mixed with 504 resin can bond PVC coated cover material.
(2) Polyvinyl alcohol (PVA) binder
Vinyl acetate is a kind of binder obtained by alcoholysis in alcohol solution at the temperature of 45-48 â„ƒ under the action of alkali catalyst.
PVA is a white flocculent or powdery polymer compound that can dissolve in water and is a colorless and transparent viscous liquid after hot melting.
The performance of PVA binder is determined by the structure of polyvinyl acetate and the degree of alcoholysis. A polymer with a high degree of alcoholysis has a very high ratio of water resistance; a low alcohol solubility (87% -89%) is easily soluble in water; when the solubility of alcohol decreases again, the solubility of water decreases.
PVA with a high degree of polymerization has a large molecular weight, good film-forming properties, high viscosity and strong viscosity, but poor water solubility. There are three types of polymerization, high, medium and low. When using PVA binders for binding, both the degree of polymerization and water solubility must be considered.
The PVA binder is a hot sol, which has a good effect on binding paper, cardboard, hardcover book shells, fabrics, etc. Because it is cooled, solidified and dried, it has a good shape.
The price of polyvinyl alcohol bonding material is cheaper than polyvinyl acetate, but its bonding strength is not as good as PVAC, but it is higher than the price of flour paste. It is a commonly used synthetic resin bonding agent for binding.
(3) 107 synthetic resin bonding materials.
107 Synthetic resin binder is a water-soluble polyvinyl formal with a transparent or yellowish transparent viscous agent. When using, you can add water and stir to get diluent.
107 adhesive has strong adhesion and stable performance. Binding can use this kind of glue to bond single pages, double pages, sweeping liner, bag cover, pulp back, etc., its effect is better than flour paste. The film has good elasticity, is not brittle, nor deliquescent. 107 glue is a hydrosol, it can not be used below 0 â„ƒ, and can not be exposed to sunlight for a long time, so as to avoid separation of the water glue, viscosity reduction, aging and deterioration.
107 glue can be adjusted according to the required viscosity when it is used. When it is too thick, water can be added (note the water temperature). When the viscosity is too low, some plasticizers are added appropriately. When it is found that the water glue is separated, a small amount of ethanol can be added to dissolve the glue block evenly.
107 glue can also be mixed with PVAC binder to increase its viscosity.
107 binders are extremely versatile and can be widely used in industries such as construction, shoemaking, and printing. The 107 gum used in the binding industry is mainly used instead of flour paste.
107 glue is generally not used for paste shells (mainly due to its water solubility, easy to penetrate, slow drying is not easy to shape, will cause the book shell to curl unevenly)
(4) EVA hot melt
EVA hot melt is made by copolymerization of ethylene and vinyl acetate under high pressure. Because ethylene and vinyl acetate are different in composition, the molecular weight of the hot sol obtained by polymerization is also different, and its performance is also different, which can be selected according to needs.
EVA hot melt is a solid meltable polymer that does not require solvents and does not contain moisture. EVA hot sol is solid at room temperature, heated to a certain degree and becomes a fluid and viscous liquid. The molten EVA colloid is a light brown translucent body.
EVA hot melt is 100% solid. When it turns into a fluid, it is completely melted by heating. When heated to 80 â„ƒ, the colloid starts to slow down. As the temperature increases, the flow gradually accelerates. When the temperature rises above 250 â„ƒ, the colloid starts to age. Deterioration, viscosity decreases, and the film becomes brittle. The curing process of the hot sol is completed by cooling. It is a fast-curing and excellent-performance adhesive material. Its drying speed is unmatched by any kind of adhesive, and it can be cured in only a few seconds. , The adhered objects are firmly bonded together.
EVA hot sol can bond both porous and non-porous materials, but the adhesive surface should not be too large. Excessive adhesive surface affects the application speed and cannot be bonded, because the curing time of this adhesive is only at most ten seconds. . EVA hot melt is mainly used in high-speed production lines, because the wireless binding line is a high-speed production equipment for the production of books and periodicals, and its speed is generally 55 books / min. The hot melt is used on this rapid processing equipment The book binding book is very suitable, it can shorten the drying time after glueing and increase the binding speed.
There are high-speed and low-speed thermosols produced in China.
According to the different texture of the adherend, it is divided into several types such as glue for offset paper and glue for art paper; there are side glue and back glue to adapt to different strength requirements.
(5) Vinyl acetate-ethylene emulsion (VAE)
VAE binder is a milky white liquid, a water dispersion system of vinyl acetate and ethylene copolymer.
The ethylene component gives the copolymer film flexibility, which is much better than the brittle polyvinyl acetate homopolymer. This emulsion is very stable, has a slight taste of vinyl acetate monomer, and can be stored for 6 months under natural conditions.
This material for binding is mainly used for bonding PVC fabrics, such as PVC coating cover paper and ring lining.
(7) Paper-plastic composite adhesive.
The paper-plastic composite binder is a copolymer of acrylic acid ester and styrene.
The appearance is white liquid. The glue has good adhesive properties and the required viscosity and film elasticity. Paper-plastic composite adhesive is water-based dispersion, non-flammable, non-toxic, non-hazardous, non-irritating odor, etc. It is a water-soluble adhesive material with strong adhesion and convenient use.
Paper-plastic compound is mainly used for binding paper and plastic in binding. This kind of adhesive can be used by manual and mechanical binding. It is easy to operate and firm in adhesion.
(8) 504 adhesive
504 adhesive is a transparent liquid adhesive, which can be used alone or mixed with other adhesives. It has a strong viscosity.
In binding, it is generally mixed with other binders. For example, after mixing 504 binder with polyvinyl acetate latex or flour slurry, it can bond paper and PVC coated paper, paper and plastic film, with good bonding effect.
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